You're absolutely right, but I am very constrained on space and needed a custom size to properly fit my needs rather than trying to fit a large blasting cabinet in my corner of the garage.

So my cost of this is around (with materials I already had) $150. I have very little space in my shop so I needed a custom solution.

I does take a little getting used to. However, I have now used this a handful of times with my orbital sander and have had zero issues. I do eventually plan on placing my belt sander in there and see how that goes.